The present invention relates to a non-contact process for cleaning polarizing glass, and in particular to an en masse cleaning process suitable for the removal of organic and inorganic matter from thin polarizing glass devices having a thickness of between 10 xcexcm to 50 xcexcm.
The thorough cleaning in the processing of polarizers or polarizing glass devices poses an especially difficult task in that such devices may be as small as 1.0 mmxc3x972.0 mmxc3x9730-50 xcexcm. Conventionally, the cleaning process of polarizers has been practiced primarily by manually washing each device individually.
An example of a polarizing glass, POLARCOR(trademark) is available from Corning Incorporated, Corning, N.Y. POLARCOR(trademark) products are available in thickness as low as 200 xcexcm. Co.-pending U.S. application Ser. No. 09/142713 entitled xe2x80x9cUltrathin Glass Polarizers and Method of Making Samexe2x80x9d, having as inventors Borrelli et al., assigned to the instant assignee, and herein incorporated in its entirety by reference, discloses a process by which polarizing glass can be thinned further to form an ultrathin polarizing glass measuring less than 50 xcexcm in thickness, preferably between about 10-40 xcexcm.
During the thinning process the polarizing glass is blocked or bonded to a substrate with a suitable material such as a rosin or a wax, or a mixture of rosin and wax. The polarizing glass is thinned to the desired thickness, preferably about 30-50 xcexcm, and thereafter sliced into wafers of about 1 mmxc3x972 mm. Prior to packaging and delivery to the customer all organic matter, such as rosin, wax, and inorganic matter, such as polishing/grinding media, and glass chips from the slicing process, must be removed from the surface of the polarizing glass wafers.
Due to the small and delicate nature of these thin polarizing glass devices, effective cleaning treatments are limited. Typically, each thin polarizing glass wafer is washed manually one at a time, a process which is not only labor-intensive and inefficient, but also costlyxe2x80x94costs which are ultimately translated to the end consumer. Further, since this manual process is a contact process, there is extensive manipulation of the devices, which increases the possibility of in-process damage and post-process contamination.
In view of the above-described disadvantages in the art, there exists an explicit need for a cost-efficient, expedient and high-volume process for cleaning thin polarizing glass devices.
Accordingly, it is an object of the present invention to eliminate the above-mentioned disadvantages by providing a thorough and highly efficient process for cleaning en masse thin polarizing glass devices. It is a still further object of the present invention to provide a cleaning process for thin polarizing glass devices that provides minimum in-process (e.g., scratching or breaking)and post-process damage (e.g., re-contamination). It is a still further object of the present invention to provide a cleaning process that is cost-efficient and transferable to large-scale production.
Other objects and advantages of the present invention will be apparent from the following description.
In accordance with the present invention, there is provided a method for en masse cleaning of polarizing glass devices including the steps of using a cleaning vessel having a porous shelf, and being capable of holding a high-volume of thin polarizing glass devices; and, exposing the cleaning vessel containing the polarizing glass devices to washing, rinsing and drying steps to remove organic and inorganic matter from the surfaces of the polarizing glass devices. As used herein the term xe2x80x9cen massexe2x80x9d means that the polarizing devices are cleaned all at once and together.
In particular the inventive method comprises the following specific steps:
providing a cleaning vessel possessing a vertical side wall and a porous shelf secured to said vertical side to form an annular cavity for containing a plurality of thin polarizing glass devices;
loading said polarizing glass devices into said cleaning device;
washing the polarizing glass devices contained in the cleaning vessel in an organic solvent;
washing the polarizing glass devices contained in the cleaning vessel in aqueous-based detergent;
rinsing the polarizing glass devices contained in the cleaning vessel in a first rinse of high-purity water;
rinsing the polarizing glass devices contained in the cleaning vessel in a dilute mineral acid rinse;
rinsing the polarizing glass devices contained in the cleaning vessel in a second rinse of high-purity water;
drying the polarizing glass devices contained in the cleaning vessel in an oven; and,
unloading the polarizing glass devices from the cleaning vessel.
The present invention is also related to a vessel capable of cleaning a high-volume of thin polarizing glass devices comprising:
a vertical side wall; and,
a porous shelf attached to the vertical side wall, such that an annular cavity is formed for receiving a plurality of said polarizing glass devices.